Department of Processing and Food Engineering, Punjab Agricultural University, Ludhiana-141 004, India
*Corresponding author's e-mail: gagandeep@pau.edu
Online published on 11 November, 2014.
The effect of sugar concentration and different drying temperatures on the quality of osmotically dehydrated sweet potato was determined. Sweet potato cubes were osmotically dehydrated in sugar syrup concentrations of 50, 60 and 70°Brix for 48 hours and thereafter samples were dried using tray drier at temperatures of 55, 65 and 75°C. The quality of the samples was determined in terms of bulk density, water activity, sugar gain, hardness, shrinkage ratio and color. The drying rate decreased with increase in drying time and became uniform for 55, 65 and 75°C drying temperature irrespective of concentration of sugar solutions, whereas at initial stage higher decrease in drying rate was found in 75°C at 50°Brix. Bulk density was maximum for sugar solution concentration of 60°Brix at 65°C (46.52 kg/m3). The maximum water activity was found for sample having sugar concentration of 50°Brix and drying temperature of 55°C and the minimum value of water activity was attained for sliced sample at a drying temperature of 75°C and sugar concentrations of 60°Brix. It was observed that the sugar gain was highest in samples dipped in sugar solutions of concentration 70°Brix and lowest in the samples of sugar solution concentration of 50°Brix.
Drying temperature, Osmotic dehydration, Sugar, Sweet potato
